41. The equation d*u P* WL occurs in finding the shape of a strut which canks a fhrmt «( the cml, *f**l »Uo ft lateral load. Show that it is satisfied by putting All the letters except u and JF represent constants. 42. If / = dt sin / + b sin a/ 4- < lin 3/f find the vahir »f ' *in4 ^, 43. If x =s r sin f / + -^ cos 2y/ — ., where * i» the i df fiftir t of piston of a steam-engine from the middle of il* »tr*»kr, f • Irngfli of er*ifiJi» / .:. Irn^fh of connecting rod, find expressions for the vritH-ity ami icrpkr^tlmi, What are the values of the acceleration when / .-. i?t ami I 2f ' ' f 44. A point motes along a straight line so that if"* ilnf»ttr.«* i fr^m « fi*f»! p»jnl on the line is given by / -- a sin (2»// »f /*} «f 1 1111 f^w// f ft) ; nt ^ /. ^ «u>:| 4 itr constants. Write down expressions ft»r the vrlodfy AIP! ar.tr-inrjfifjfi *| tfif Mm**. Plot a curve to show the Talue of s fc»r any value of / whrn tf : ^ 1*5, 1 ... cifi, 4* **7>J* /5 = 0*951,7= ?. 113.(DilTerontiation of log M, If / is a function of a*, and ty and i.r are iiintiltani*ftti't and 3?) then nf This remains true as 9f and «r are Mm approaches the limiting value '/• *" rf,r 7T dy Let/ • !og4 . Then ,r /* ,*/i liliil . . <* sc r r/r . ^/F .... f I r/r i7r r ^ It follows in the same way that im iiwl »tttattcr9 t